Let's say that a team does an accurate job of assessing the top 200 players in a draft, and that out of those top 200, through extensive analysis finds that only 25 are actually strong possible fits for your scheme or your selection criteria. The other 175 on the board, if on your team, wouldn't be good fits or would be sub-optimal, so you basically ignore or de-value them.
If you are sitting at #10 and you estimate that your next highest-ranked 'fit' player will be picked within the next 5, 10, or even 25 picks, it doesn't matter if other people think you are reaching. You are picking the best player on your board, for your team. What good does it do to pick the best talent regardless of fit, when you are trying to build a team that excels in your specific scheme or organizational mission/philosophy?
A team that truly believes in its own values, system, and organization will not hesitate to pass over who 3rd party observers consider to be superior talent. The entire debate of who was a reach, does not matter. It does not matter if people think picking Seymour, Warren, Watson, Mankins, Mayo came out of nowhere, if the Pats thought those highest ranked fit players would not last to the next round.
The only analogy I can give as additional explanation is think of a fantasy baseball draft. If pre-draft I know that I want to build a team with excellent pitching, on base percentage, and steals, I will value those players higher than other teams do. If I highly value Chone Figgins for his potential contributions under my team strategy, and I know he won't last through the next round, it doesn't matter if I pick him much higher than is expected. Even if people think I am 'reaching' on picks, I am building my team under my vision, and picking players I know will not last if I do not pick them in those specific rounds.
If the NEP truly believe - and I really, really hope they don't - that out of the top 200, only 25 - or even 50 - are worthy of selection, then they are needlessly narrowing their available talent pool, much as the European royalty did in the 19th century, whereby their offspring - because of inter-marriage & inbreeding - became ******ed & crippled. Whatever happened to: "Give me a kid with talent and the willingness to succeed, and I can develop him into a player I can use"? And what if those 25 - or 50 - are gone by the end of the 3rd round? What do they do then, throw darts at names? That would help explain the Slater & Ruud picks. Perhaps the FO & coaches need to widen their scope and consider other sources.
There is a big difference btwn. estimating that your next target will be selected within the next 5-10 picks, and within the next 25 picks, which is almost a full round away. In the case of Mayo, it was almost certain that he would be gone by #15. At #10, the only 2 guys I wanted were McKelvin or Mayo. The FO had already traded down once; there was no reason to trade down again. In the case of Wheatley, however, there was no reason to think that he wouldn't be available at #78: he just wasn't that well-regarded, esp. because of his wrist. The better move would have been to trade down from #62, or draft someome previously unconsidered, but with considerable talent, e.g. RB Jamaal Charles, the Lightning to LaMa's Thunder. At #78, Wheatley would've represented better value; and either Shawn Crable would have still been available at #94, or Detroit, instead of drafting OLB Cliff Avril at #92, would have taken local kid Crable, leaving Avril - who was better-regarded by many of us over Crable, anyway - for the NEP. Either way, our need at pass-rushing OLB is filled, and we gain a home-run threat at RB/Returner, at the cost of just a 2nd-string - or 3rd- or even 4th-string - QB. And besides, sometimes you just gotta call the other team's bluff.
In the cases of the rest of the picks, the FO needs to do a better job of recognizing those 4 guy's places in the draft universe relative to the other 31 teams. The FO cannot just have their list and not deviate from it, as if it were in a vacuum, and not take note of how the rest of the draft is unfolding. There were several quality talents who could've been very good fits for the Pats' scheme/system on both offense & defense, and who were bypassed in favor of (much) lesser talents who were also (apparently) good fits, but were taken just too damn early. There's little doubt in my mind that Jon Wilhite, for instance, would've been available at the end of the 5th round. OG Roy Schuening, as Steven Neal's replacement, would've been a better choice, as would've been CB Orlando Scandrick.
As for the out-of-nowhere selections of $eymour, Warren, Watson, Mankins and Mayo, they may have been somewhat earlier than expected, but they were hardly unknown, and none would've been available when the Pats selected next, due mostly to those next selections having been traded, either already or shortly thereafter. However, in the case of Bennie Watson: I would have taken LB Karlos Dansby then, and I would take Dansby now.